User:Sheetal Patil

For a Biochemistry project at UMBC, here is information on competitive inhibtion at the active sites for Glutamine Synthetase enzyme.

 Exercise 1

Secondary Structure

Exercise 2

Structure with Labels

Exercise 3

Active Site Residues

Exercise 4

Salt Bridge Between Residues

Explanation:

Competitive inhibition takes place when a molecule that is structurally similar to the substrate for a particular reaction competes for position at the active site on the enzyme. Sites that ligands are allowed to bind can be shown here: Ligand Sites. This ties up the enzyme so that it is not available to the substrate. Competitive inhibition can be reversed if the concentration of substrate is raised to sufficiently high levels while the concentration of the inhibitor is held constant.

Studies in competitive inhibition of glutamine synthetase show that glycine, L-alanine, and L-serine are all inhibitors competing for the same binding site for L-glutamate. They are also competing to bind to GS-ATP. These sites can be seen on the molecule here. (Insert wiki text) L-alanine specifically does not show any affinity to GS that is substantially lower than that of glutamate. Also, no significant conformation change is shown by the binding of these competitive inhibitors other than the movement of Asn-264.